Critical Role of the Presynaptic Protein CAST in Maintaining the Photoreceptor Ribbon Synapse Triad.

The cytomatrix at the active zone-associated structural protein (CAST) and its homologue, named ELKS, being rich in glutamate (E), leucine (L), lysine (K), and serine (S), belong to a family of proteins that organize presynaptic active zones at nerve terminals. These proteins interact with other active zone proteins, including RIMs, Munc13s, Bassoon, and the ß subunit of Ca2+ channels, and have various roles in neurotransmitter release. A previous study showed that depletion of CAST/ELKS in the retina causes morphological changes and functional impairment of this structure. In this study, we investigated the roles of CAST and ELKS in ectopic synapse localization. We found that the involvement of these proteins in ribbon synapse distribution is complex. Unexpectedly, CAST and ELKS, in photoreceptors or in horizontal cells, did not play a major role in ribbon synapse ectopic localization. However, depletion of CAST and ELKS in the mature retina resulted in degeneration of the photoreceptors. These findings suggest that CAST and ELKS play critical roles in maintaining neural signal transduction in the retina, but the regulation of photoreceptor triad synapse distribution is not solely dependent on their actions within photoreceptors and horizontal cells.

The Impact of COVID-19 on Dental Anesthesiologists: An Online Survey of Board-Certified Dental Anesthesiology Specialists of the Japanese Dental Society of Anesthesiology.

OBJECTIVE: The impact of the COVID-19 pandemic on dental anesthesiologists has not been examined. This study aimed to determine how the COVID-19 pandemic affected Japanese dental anesthesiologists' professional lives. METHODS: An online questionnaire related to the effects of COVID-19 on dental anesthesiologists' professional lives was emailed to 351 board-certified dental anesthesiology specialists from the Japanese Dental Society of Anesthesiology. The endpoints of this study were changes in income and job satisfaction as a dental anesthesiologist from 2019 prior to the COVID-19 pandemic. RESULTS: A total of 141 dental anesthesiologists participated in the survey. Most respondents reported no change in income relative to 2019 for 2020 or 2021. Significantly more dental anesthesiologists reported income decreases relative to 2019 for 2020 (39%) vs 2021 (21.3%; P = .001). Very few dental anesthesiologists reported income increases relative to 2019 for 2020 (2.1%) vs 2021 (15.6%; P < .001). Job satisfaction as a dental anesthesiologist remained unchanged for all 3 years. CONCLUSION: Even though many Japanese dental anesthesiologist specialists lost income because of COVID-19, they maintained their job satisfaction.

Preparation and Evaluation of Stomatitis Film Using Xyloglucan Containing Loperamide.

Stomatitis induced by radiation therapy or cancer chemotherapy is a factor in sleep disorders and/or eating disorders, markedly decreasing patient quality of life. In recent years, disintegrating oral films that are easy to handle have been developed; therefore, we focused on the formulation of these films. We prepared an adhesive film for the oral cavity using xyloglucan (Xylo), which is a water-soluble macromolecule. We used loperamide, which has been reported to relieve pain caused by stomatitis effectively, as a model drug in this study. Films were prepared from Xylo solutions (3% (w/w)) and hypromellose (HPMC) solutions (1% (w/w)). Xylo and HPMC solutions were mixed at ratios of 1 : 1, 2 : 1, or 3 : 1 for each film, and films 2×2 cm weighing 3 g were prepared and dried at 37°C for 24 h. Physicochemical properties such as strength, adhesiveness, disintegration behavior, and dissolution of loperamide from films were evaluated. Films prepared from Xylo solution alone had sufficient strength and mucosal adhesion. On the other hand, films prepared from a mixture of Xylo and HPMC were inferior to those made from Xylo, but showed sufficient strength and mucosal adhesion and were flexible and easy to handle. The films prepared in this study are useful as adhesion films in the oral cavity.

Interaction of ethyl pyruvate in vitro with NF-κB subunits, RelA and p50.

Ethyl pyruvate, an aliphatic ester derived from pyruvate, reportedly has anti-inflammatory actions through inhibition of the transcription mediated by nuclear factor-kappa B (NF-κB). It was suggested that ethyl pyruvate inhibited NF-κB/DNA-binding activity through the covalent modification of RelA. However, the interaction of ethyl pyruvate with RelA in vitro has not been reported. In the present study, we confirmed that treatment of cultured alveolar epithelial cells, A549 cells, with tumor necrosis factor α (TNFα) increased the NF-κB/DNA-binding activity. When the nuclear extract of the cells was incubated with ethyl pyruvate, the NF-κB/DNA-binding activity was strongly inhibited. Because we previously found that the NF-κB/DNA complex included RelA and p50, we bacterially expressed a deletion mutant of RelA, RelA (1-220), and a full-length form of p50. Incubation of RelA (1-220) or p50 with ethyl pyruvate induced dramatic changes in mobility in two types of nondenaturing gel electrophoresis. Electrophoretic mobility shift assays revealed that incubation of RelA (1-220) or p50 with ethyl pyruvate inhibited the DNA-binding activity. Furthermore, immunostaining of A549 cells revealed that ethyl pyruvate inhibited the nuclear association of RelA after TNFα treatment. These results suggest that ethyl pyruvate interacts with RelA and p50 to inhibit their functions at multiple points.

Inhibition by ethyl pyruvate of the nuclear translocation of nuclear factor-kappaB in cultured lung epithelial cells.

Tumor necrosis factor alpha (TNFalpha) is a cytokine inducing inflammatory responses. It has been reported that ethyl pyruvate has anti-inflammatory actions through inhibition of the transcription mediated by nuclear factor-kappa B (NF-kappaB). By reporter gene assay, we first confirmed that TNFalpha activated the NF-kappaB pathway in cultured alveolar epithelial cells, A549 cells. This activation was strongly inhibited by ethyl pyruvate in a concentration-dependent manner. Treatment of the cells with TNFalpha-induced phosphorylation and degradation of IkappaBalpha within 15 min. The level of IkappaBalpha protein was increased from 30 min, suggesting an increase in the NF-kappaB-mediated transcription of IkappaBalpha. Ethyl pyruvate did not affect the changes in IkappaBalpha within 15 min, but strongly inhibited the increase in the IkappaBalpha protein level from 30 min. An immunoblot analysis revealed that ethyl pyruvate inhibited the nuclear translocation of RelA from 5 min of the treatment with TNFalpha. These results strongly suggested that ethyl pyruvate inhibited the NF-kappaB pathway through inhibition of the nuclear translocation of RelA. Ethyl pyruvate may be a good therapeutic drug for inflammation in which activation of the NF-kappaB pathway is involved.